It seems to me that every night I see a picture of a tornado on TV or on the internet. This makes me wonder - Have the number of tornadoes gone up over the past years or is it simply that some went unreported? Any opinions?

I would go with more people reporting them. The climate is not changing so much that tornadoes are appearing from nowhere. Storm chasing is getting a cult following now. Every storm has a chaser looking for a tornado.